Thanks much Turnagain.
It must then be that my double, a 12 bore, 2 1/2 inch gun with original barrels and nitro proofed, is over a hundred years old? This seems remarkable for a gun in this condition and proofed for nitro powder (and BP)without having been sleeved or rebaralled? I was estimating, based on above and having so much cc that the gun was about fifty years old? Would there be a way to fairly accurately date my double? Its SN is 4372.
Ed